Process for refining mineral lubricating oils



Patent ed July 13,192

" UNITED STATES 1,592,05&

PATENT orr cs JAMEs W. WEIB, or FILLMORE, cALiroImIA;

, rnociiss roa Bar um; MINERAL ULUBRIQATING oILs.

No Drawing. i

This invention relates to the manufacture of lubricating oils, andrefers particularly to improvements in the treatment of lubrieating oilstocks frommineral or petroleum oils with sulfuric acid.

In the treatment and refining of lubricating' oil stockswith mineralpetroleum oils,

the stock is commonly treated with. sulfuric acid. The sulfuric acid isadded to the lubricating oil stock and the admixture agitated for aperiod of time until the purification reaction substantially ceases. Asaresult of such reaction, a quantity of sludge or partiall spent acid isformed. The strength 0 sulfuric acid in the produced sludge, while attoo low a potential strength for further refining of the lubricating oilstock commingled therewith, still possesses considerable potentialstrength in reference to its ability to treat untreated lubricatingstock, or certain treated or untreated stocks of d-ijferent grade.-

Inan ordinary process of refining,-however, this residual sulfuric acidstrength'of the sludge is not utilized. Moreover, in the practicalapplication of acid in the treatment of lubricating oil' stocks, it isdifficult to apply the acid to the stock so as to secure a substantiallyand economical efliciency in the reaction between the lubricating oilstock and acid without at the same time causing a violent reaction to.take place.

- The effect of-a too vigorous reaction bestock would possess an olivegreen bloom -or- =tween sulfuric acid and certain oil stocks imparts tothe stock a bluish fluorescence or bloom, whereas otherwise thelubricating oil fluorescence by reflected light. Lubricating oil withabluish fluorescence or bloom is generally considred' of low grade in themarket.

.Itis an object of the present invention -.to provide a method oftreating lubricating .7 that thisformation or imparting of a bluish oilstocks'vby which the sulfuric acid em-- ployed is more efficientlyutilized and by whicha modified action of surfuric acid upon lubricatingoil stocks is obtained, so

' fluorescence or bloomv to the finished stock is-avoided and a superiorlubricating oil. lower rate of acid stock thus provided at aconsumption. V The vprocess is articularly adapted 't0 the.treatment ofubricating oils wherein tional lu fining Application filed May. 14 1925,Serial No. 30,855.

it is desired to produce a lubricating 011 of intermediate viscosity orcolor from a stock of, low viscosity and light color and a stock ofrelatively high viscosity and dark color.'

It has hitherto been particularly difficult to treat, for example, heavysteam refined stock to a relatively light color as compared to theoriginal stocks. Attempts to refine,

treat and filter to such a. comparatively light.

produce a stock of the undesired or bluish fluorescence. The methodeffects a modified sulfuric acid treatment secured by mixing such heavystocks with an admixture of lighter, less viscous stocks and sulfuric.acid sludgeresulting from the treatment of such light stock withsulfuric acid. The mass is then agitated together so that the acidsludge willetfect a purification of the heavy v1s-.

cous stock under conditions which are found to substantially retard theimparting ofa bluish fluorescence or bloom to the resultant product.This is due. to the presence of the less viscous stock and the fact thatthe potential sulfuric acid strength of the sludge is materiallyreduced.v

The invention is particularly useful inconnection. with the productionof blended intermediate stock from the use of a light.

and heavy oil stock. The method of treatment or modified'sulfuricacidtreatment, however, may be .utilizedwherever, follow ing a sulfuric acidtreatment of. one lubri-.

eating oil stock and-prior to the removal of thesludge formed thereby,any other addiand the mass agitated together. for the recase, theresultant action upon the second stock'is obtained, through a treatmentthereof by a hitherto waste material, the urifi-' ricatingloil stock isadded thereto of said additional stock. -In any cation beingaccomplished withoute acting or illustration of a process embodyingtheinvention.

'Lubricating oil' stock of relatively low viscosity is commingled withapproximately fifteen pounds of sulfuric acid per barrel of stock undertreatment and maintained in intimate contact for approximately fortyfiveminutes. The stock is then allowed to settle, after which the sludgeresulting from this acid treatment is preferably withdrawn. Thenapproximately twenty pounds of su lfuric'acid per barrel of stock isadded'and similarly commingled and maintained in intimate contact withthe oil stock for ap proximately forty-five minutes. "Then while the oiland admixed acid are still being com-V mingled and maintained inintimate contact,

filtered cylinder stock or lubricating oil stock' of relatively highviscosity is added and commingled with the first stock and sludgetherefrom while still remaining therein for aperiod of approximatelyforty-five minutes. For example, 20% by volume of the second stock maybe added. In this way, the sludge produced from the second sulfuric acidtreatment of the first or lighter oil stock is caused to purify thesecond or added heavier oil stock, the purification thus being effectedby a comparatively valueless material, ahd the sulfuric acid employedbeing more efiiciently utilized. Mereover, the resulting action is foundto be substantially less vigorous and proceeds without the im parting ofa bluish fluorescence or bloom to the blended finished stock.

Subsequent to such treatment, the sludge is permitted to settle from theoil stock and is then withdrawn.

After such an acid treatment, the lubricating oil stock may be finishedby any preferred method, such for example, as washing or athering bywater and neutralization wit an alkali soda, but preferably is finishedin the following manner:

There still remains suspended in the oil a certain percentage of finelydivided sludger or pepper which will not settle out of the lubricatingoil stock and should be removed 7 to obtain a lubricating oil of highpurity. This pepper may beremoved by gathering the same with acomminuted solid adsorbent material, the same being agitated with thestock at a temperature below the decomposing temperature of the sludgepresent. The comminuted solid adsorbent material may be added at'therate of one ton of the solid substance to thirty thousand allons of theoil stock. Comminuted granite, diatomaceous earth, gdecolorizing claysor fulthe sulfur dioxide.

'lers earth are examples of solid materials which may be employed. Thecomminuted substance, with the sludge gathered and ad hering thereto, isthen separated from the oil stock.

The oil stock still contains a quantity of 7 acid reaction products oracid'sludge in colloidal suspension or otherwise remaining in pose andliberate carbon dioxide. The .de-

composing sludge will adhere to the comminuted substance commingled withthe oil and can then be removed, 7

The temperature of the treatment is 180 F. or above and may be as highas any temperature below the vaporizing temperature of theoil stock,although relatively i lower temperatures, such as 300 F. are preferred.During the agitation of the oil and solids together, an inert gas may beblown through the same to assist in the removal of Subsequent to suchtreatment, the lubricating oil stock is separated from the remainder ofthe mass and then, if necessary, is brightened by blowing with air inthe usual manner.

This method of removing acid reaction products from the oil byadsorption with a comminuted solid substance is accompanied by nochemical reaction, and therefore no injurious compounds are formed whichre main inthe oil or require removal by further process.

While I have described in detail the preferred method of refininlubricating oils, it is understood that various modifications may bemade in the details of the method and process, without departing fromthe spirit of the invention, and the invention is therefore not limitedto the specific details set forth for the purpose of illustration, butincludes all such modifications and substi tutions .as come within thescope of the apstocks, which comprises treating relatively low viscositylubricating oil stock with sul-' furic acid until the action of the acidupon said stock is substantially complete, then' without removing theproduced sludge from said treatment introducing relatively highviscosity lubricating 'oil stock to the admixture and commingling thesame therewith, whereby the added oil stock is reacted upon by the acidsludge .resulting from the sulfuric acid treatment of the originalstock.

- sulfuric acid and then,

lubricating oil stockto stock from the resultant sludge.

3. The method of refining a lubricating oil stock; which comprisestreating relatively low viscosity lubricating oil stock with withoutremoving the produced 'sludge from such treatment, adding-asecondrelatively high. viscosity the admixture and continuing-the treatment,settling and removing the major portion of the sludge, and

then gathering and removing a further quantity of the sludge remainingin the oil stock'by treatment with comminuted solid adsorbent material.

4. The method of refining a lubricating oil stock, whichcomprises'treatin a lubricatlng oil of relatively low viscosity withsulfuric acid, then without removin thesludge, adding a lubricating oilof relatively higher viscosity, settling and removi g the major portionof the sludge, and gathering and removing a further quantity of theremainierof the sludge by the treatment with com- 'mi'nuted solidadsorbent material. 5. The niethod of refining lubricating oil stock,which comprises treatinga lubricating oil of relatively low viscositywith sulfuric acid, then without removing the sludge adding alubricating oil viscosity and continuing the treatment, sepaofrelatively higherrating the major portion of the sludge there-- from,commingling the lubricating'oil stock with a comminuted solidadsorbentmaterial at a temperature suflicient-to decompose the sludgepresent, and separating the adsorbent material with the materialadsorbed 'f-rom' the oil stock. v

6. The method of refining lubricating. 011

stocks, which comprises treating a lubricating oil of relatively lowviscosity with su lfuric acid, then without removing the sludgeproduced, adding a lubricating oil of relatively higher viscosity andcontinuing the treatment, removing the major portion of the sludgetherefrom, and gathering the suspended sludge from the lubricating oilstock by adding and commingling therewith a comminuted solidadsorbentmaterial at a temperature below the "decomposing tem-' peratureof the sludge.

7. The method of refining lubricatingoil stocks, which com risestreating a lubrieat-' ing oil of relative v low viscoslty with stilfuric acid, then without're'moving the sludge,

, adding a lubricating oil of relatively higher viscosity and continuingthe-treatment, re-

moving the major portion of thesludge formed. gathering the suspendedsludge adding and commingling therewith a solid adsorbent material at atemperature below the decomposing temperature of the sludge,. removingthe adsorbent material and gathered .sludge, agitating. the oilstockwithcomminuted solid adsorbent material at a temperature sufiicient'todecompose the remaining sludge and liberate sulfur dioxide, and thenseparating the oil stock from the mass.

Signedat Los A geles, 'Galif., this 4- day of May 1925.

JAMES W. 'WEIR.

